Wannon Water's aquaculture program wound up in late 2017 after nine years of research.
The innovative project showed that aquaculture can improve the quality of recycled water and reduce the reliance on expensive mechanical de-sludging of sewage lagoons.
Wannon Water agreed to explore the concept in a partnership with Deakin University, successfully pioneering the use of goldfish to reduce sludge during tank trials in Hamilton.
The aquaculture program was then scaled up, allowing Wannon Water to produce its own goldfish at a hatchery in Warrnambool and grow them out at a juvenile fish production facility in Hamilton.
Goldfish were released into the Hamilton primary effluent lagoon and, later, in a controlled trial at the Port Campbell primary effluent lagoons. The more colourful goldfish were sold into the aquarium market to provide additional revenue for the project.
In addition, Wannon Water was able to successfully breed carp X goldfish hybrids, specifically designed for an effluent lagoon environment.
The Port Campbell trial has now concluded according to the project schedule and in-lagoon data has been collated and analysed.
The research found that a carp-goldfish hybrid appears to have the most potential for sludge reduction.
Wannon Water will share the findings from the project with the wider water industry and recommend that hybrids should be the focus of future research and development efforts.